PRODUCT  :  Borland C++                           NUMBER  :  1170
  VERSION  :  3.1
       OS  :  DOS
     DATE  :  October 22, 1993                         PAGE  :  1/3

    TITLE  :  Solving keyboard conflicts in the IDE.






  QUESTION:
  ========
       Sometimes when using the arrow keys in the IDE I get strange
  effects, such as the shift key getting stuck on (so that
  everything comes out in capitals) or perhaps numbers come out
  sometimes.  I see things like going through text with an arrow
  key and then sometimes it starts to highlight everything.  Why is
  this happening and what can I do about it?

  ANSWER:
  =======
       When you use the computer's keyboard, 1 or 2 or 4 interrupts
  are generated when the key goes down, and also when the key goes
  up.  The machine tries to figure out from the scan codes what key
  was hit, and what action to take on it.
       Upon occasion, for various reasons, some of these interrupts
  may not be responded to and some of the scan codes may be lost.
  If some of the scan codes are lost, an arrow-key keystroke may
  look to the machine like a number key, or like a shift key going
  down (and not coming back up).  So when the machine sees the
  shift key going down, it assumes you are holding it down, so your
  arrow looks like a shift-arrow and the block should be
  highlighted.  Or you may type in capitals when you did not intend
  to.



  QUESTION:
  =========
       So why are the interrupts not being responded to?

  ANSWER:
  =======
       Because one scan code has not been dealt with by the time
  the next one comes along.  The IDE traps the interrupt and it has
  a fair amount of processing to do;  other TSR's that also deal
  with the keyboard (anything that responds to a hotkey or changes
  the way the keyboard works, like DOSKEY) slow down the keyboard
  response.  Your expanded memory manager, such as EMM386 or QEMM,
  also has a role to play;  the IDE has to switch modes from














  PRODUCT  :  Borland C++                           NUMBER  :  1170
  VERSION  :  3.1
       OS  :  DOS
     DATE  :  October 22, 1993                         PAGE  :  2/3

    TITLE  :  Solving keyboard conflicts in the IDE.




  protected to real mode to handle the key and it must do this
  through the expanded memory manager if the latter is present.
       The number of interrupts coming in also makes a difference.
  The arrow keys usually generate 4 interrupts per keystroke (2
  down, 2 up) but when NUMLOCK is on, they generate 8 interrupts
  per keystroke.  So one solution is to take NUMLOCK off, or simply
  to reduce the repeat rate.
       Your hardware also makes a difference.  Your keyboard should
  not be  sending more keystrokes until the previous one has been
  acknowledged but unfortunately not all keyboards behave that way.



  QUESTION:
  =========
       Just tell me what I have to do.

  ANSWER:
       Short term solutions:
       >    When the shift state gets toggled, just tap the shift
            key to reset it.
       >    Turn off NUMLOCK.
       >    Use the keypad arrow keys instead of the extended arrow
            keys.
       >    Use the /IA and /U8  (Ignore A20 and Unusual 8042)
            options with QEMM.
       >    Take out your expanded memory manager entirely.
       >    Take out TSR's that use hotkeys or change the behavior
            of the keyboard, such as DOSKEY.  (4DOS or NDOS is
            recommended if you like DOSKEY's  features.)
       >    Slow down your keyboard autorepeat (often settable in
            CMOS BIOS options) or take out a utility that speeds up
            the keyboard repeat.

       Longer-term solutions:
       >    Try a different keyboard.  Borrow a friend's, and see
            if you get better results.  If that helps, consider
            upgrading to that style of keyboard.
       >    Try a different BIOS (BIOS upgrades run less than $50,
            and may give you additional features) or change the
            keyboard BIOS.
       >    Try using the DOS TSR KEYB.  From the dos directory,
            type "KEYB US,,KEYBOARD.SYS".  This will install a













  PRODUCT  :  Borland C++                           NUMBER  :  1170
  VERSION  :  3.1
       OS  :  DOS
     DATE  :  October 22, 1993                         PAGE  :  3/3

    TITLE  :  Solving keyboard conflicts in the IDE.




            software keyboard handler that will be slightly slower,
            but may work better with the compiler.


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